钢纤维掺量对活性粉末混凝土断裂性能的影响

Influence of Steel Fiber Content on Fracture Properties of RPC

关键词:  活性粉末混凝土  钢纤维  蒸养  抗断裂性能  黏结强度  界面过渡区

Key words:  reactive power concrete  steel fiber  steam curing  fracture resistance  bonding strength  transition zone

摘要:

采用三点抗弯试验，研究了不同钢纤维掺量对活性粉末混凝土（RPC）抗断裂性能的影响；通过扫描电镜（SEM）对钢纤维与RPC基体的黏结情况进行了研究；通过拉拔试验得到了钢纤维与RPC基体的界面黏结强度.结果表明：对于素RPC，其脆性大，断裂能值低，蒸养使其脆性增加；掺加钢纤维后，蒸养可改善钢纤维与RPC基体的界面过渡区，增加界面黏结强度，使钢纤维被拔出需要消耗更多的能量，从而提高了RPC的抗断裂性能，与钢纤维掺量为1%（体积分数）相比，当其掺量为2%时，蒸养对提高RPC抗断裂性能的作用不显著.

Abstract:

Three point bending test was used to investigate the effect of steel fiber content by volume on the cracking resistance of reactive powder concrete（RPC）. Scanning electron microscopy was employed to study the bonding between the steel fiber and the cementitious matrix. The bonding strength was examined via fiber pull out test. The results show that unreinforced RPC is brittle and low in fracture energy, and the steam curing makes RPC even more susceptible to brittle failure. On the other hand, steam curing can improve the transition zone in the PRC matrix that immediately surrounds the steel fiber. Thus heat treatment improves the bonding between the fiber and the PRC matrix, resulting in better fracture resistance. In comparison with specimens with 1% steel fiber volume faction, when the volume fraction of steel fiber is 2%, heat treatment can no longer give notable improvement of the fracture resistance of RPC.